Instrument mounting and an element thereof



March 30, 1954 H. SPASTURCZAK 2,573,702

INSTRUMENT MOUNTING AND AN ELEMENT THEREOF Filed Oct. l2, 1951 3Sheets-Sheet l L... ygumr Ill-IIIIIIIIINI 1N VEN TOR.

March 30, 1954 H.`s. PAsTuRczAK 2,673,702

INSTRUMENT MOUNTING AND AN ELEMENT TMEREoF Filed oct. 12, 1951sheets-'sheet 2 36 6g /38 511 6o im 9g 70 83 2 66 65 g .110 JDO i011 106108 85 20 76 70 102 8O i2 Til 6 132 INVENTOR.

March 30, 1954 H. s. PAsTuRczAK 2,673,702

INSTRUMENT MOUNTING AND AN ELEMENT THEREOF Filed 001;. 12, 1951 3Sheets-Sheet 3 Sigg. f2.

INVENTOR.

Harry 5 Pazlufcjaf Patented Mar. 30, 1954 INSTRUMENT MOUNTING AND ANELEMENT THEREOF Harry S. lasturczak, East Moline, ill.

Application October 12, 1951, Serial No. 251,016

9 Claims.

The present invention relates to instrument mountings for adiustablysupporting instruments of various kinds, especially cameras and opticalinstruments such as telescopes, binoculars and thelike.

The invention is designed as an improvement over the instrument mountingshown and described in my prior Patent No. 2,524,473, dated October 3,1950, for Instrument Mounting. lin this patent there is illustrated aninstrument mounting o the type in which the instrument is capable ofadjustment about both vertical and horizontal axes, together with meansfor holding or locking the instrument in any desired position oiadjustment relative to both the vertical and the horizontal axes.Selectively operable trigger-operated releasing means are provided whichis capable of being set or conditioned so that, upon operation of thetrigger, the locking means which holds `the instrumentagainst bothhorizontal and vertical swinging movements are simultaneously releasedto permit universal adjustment oi the instrument. Alternatively, thetrigger-operated releasingr means is capable of being conditioned or setso that. the locking means which holds the instrument against panoramicswinging movement in azimuth is permanently disabled and does not comeunder the control of the trigger so that the latter may control only thelocking means which holds the instrument against tilting movements inelevation about a horizontal axis.

The structure and functionoi the present invention is generally similarto the structure and function 0I" the inventionv shown and described inthe above-mentioned patent, but in the present instance certainrennements have been incorporated which render the instrument mountingmore efficient in its operation, more readily susceptible to economicalmanufacture and simpler to manipulate in attaining the desired function.It is therefore among the principal objects of the present invention toimprove instrument. mountings of the character shown in the above patentin: various respects sol as to simplify the construction of the variousparts, to improve their cooperative action, as well as to iaoilitatetheir manipulation when in use.

Briefly, the instrument mounting shown in the above-mentioned patentincludes among other things an elbow structure having a verticalv leganda horizontal arm and on which. the instrumentis mounted by means ofsuitable supporting mechanism. ,The .1 elbow is. capable oi' rotationabout its vertical leg to attain horizontal swinging movement orpanoramic sweep of the instrument and the supporting structure for theinstrument is rotatable about the horizontal arm to attain horizontaltilting adjustment of the instrument. The elbow is split longitudinallythrough the middle andthe metal oi the elbow at the split edges thereofis relieved on both sides vof the base of the elbow to provide a rockingor fulcrum axis which functions,A when the split sections of thehorizontal arm are brought together to spread the split sections of thevertical leg and vice-versa. When the split sections of the horizontalarm are compressed or brought together, the consequent spreading of thesplit sections of the vertical leg causes them to bind against the innerwall of. the tubular mounting of the elbow so that the latter is lockedagainst .rotation about a vertical axis and so that the instrumentitself is held against panoramic sweeping movements.

The structure of this patent further includes trigger-operated lockingmeans which is normal- 'ly eiective to maintain the sections of thehorizontal arm of the split elbow in a contracted or compressedcondition so as to spread the sections of the vertical leg against thewall of the elbow mounting and thus lock the elbow against turningmovement about the axis ofthe vertical leg. The trigger operated lockingmeans is capable, upon operation of the trigger thereof, to release thecompressional forces normally applied to the sections of the horizontalarm. so

as to relieve the binding action of the sections of the vertical legupon the wall of the elbow mounting and permit turning movement oftheelbow about a vertical` axis. 'Control means are provided forpermanently spreading the sections oi 'the horizontal arm so as topositively contract the sections of the vertical leg and thus render thetrigger operated locking means incapable of spreading them so thatpanoramic sweeping movements of the instrument. are available regardlessof the operation of the trigger-operated locking means which, under suchconditions`, is eiiective only to control the locking or releasing ofthe instrument against tilting Ymovements in elevation about ahorizontalY axis. rIhe present invention involves an. improved form ofsplit elbow structure, together with an improved' cooperating spreadingmeans for effecting Yspreading of the split sections of the horizontalarm thereof wherein the operations of machining the various. partsinvolved are greatly simplified.

The provision of anelbow construction and f a spreading means thereforo'f the character briefly outlined above being among the principalobjects of the present invention, another object thereof is to provideSuch a spreading mechanism which will accomplish the functions of theearlier mechanism in a simplified manner and with less complexity ofmanual control.

Another object of the invention is to provide an instrument mounting ofthe character briefly outlined above in which the mating sections of thesplit elbow are inherently in themselves held against axial shiftingmovement along one leg of the elbow and in which the fulcrum axis isincapable of shifting.

Another object of the invention is to provide a novel method of formingsplit elbow constructions designed for use in connection with instrumentmountings in the manner indicated briefly above.

Other objects of the invention not at this time enumerated will becomereadily apparent as the nature of the invention is better understood.

In the accompanying three sheets of drawings forming a part of thisspecification, one embodiment of the invention has been shown.

In these drawings:

Fig. 1 is a side elevational view of an instrument mounting constructedin accordance with the principles of the present invention;

Fig. 2 is a fragmentary side elevational view of the structure shown inFig. 1 as viewed from the left hand side thereof and showing the samemounted on a tripod or similar support;

Fig. 3 is a side elevational view similar to Fig. 2 with certain partsthereof being shown in section to more clearly reveal the nature of theinvention;

Fig. 4 is a sectional view taken substantially along the line 4 4 ofFig. 2;

Fig. 5 is a sectional view taken substantially along the line 5 5 ofFig. 1;

Fig. 6 is a sectional View similar to Fig. 5 with the parts shown in adifferent position;

Fig. '7 is a composite view including a sectional view takensubstantially along line 1 1 of Fig. 5 and an end elevation of the lockcontrol mechanism when conditioned in accordance with the disclosure ofFig. 5;

Fig. 8 is a composite view including a sectional view takensubstantially along the line 8 3 of Fig. 6 and a side elevational viewof the lock control mechanism when conditioned in accordance with thedisclosure of Fig. 6;

Fig. 9 is an expanded end elevational view of a split elbow constructionemployed in connection with the present invention.

Fig. 10 shows full size views, in elevation, of the inner faces of bothsections of a split elbow forming a part of my invention, the said viewsillustrating portions of a fractured vertical rib on each section,whereby the rib in the assembled relation of the elbow sectionsconstitutes a fulcrum for pivotal movement of said sections.

Fig. 11 is a full size plan View of the elbow section shown in Fig. 10arranged in the assembled relation shown in Fig. 5, the ends of thehorizontal arm of the elbow being moved together to emphasize thepivotal action of the elbow sections with respect to each other; and

Fig. l2 is a view similar to Fig. 11, but illustrating the elbowsections moved to another position about their fulcrum axis.

The improved instrument mounting comprising the present inventioninvolves in its general organization a two-piece split tting or elbow I0which, when assembled in the IlSi/lllmtlnt mounting, includes acomposite vertical leg I2, a composite horizontal arm t4 and a compositeconnecting elbow portion IE. The leg E2 is telescopically received andsupported in a base socket member I8 in which it is retained by means ofa keeper screw 20 which extends through the base and into an annulargroove 22 provided near the lower end of the` leg I2. The elbow I0 isthus capable of rotational movements about the vertical axis of thesocket member I8 for panoramic sweeping movements of the camera or otherinstrument as will be described presently. The arm I4 receives thereovera self-braking locking collar 24 on which the instrument is adjustablymounted and the locking collar is capable of tilting movements about thehorizon tal axis of the arm I4, when released for such tilting movement,or of being locked to the arm I4 against tilting movement thereon in amanner and for a purpose that also will be set forth presently.

The adjustable mounting for the instrument on the locking collarassembly 24 forms no part of the present invention and reference may bchad to the above mentioned patent for a full disclosure thereof.However, for convenience of description it may be stated briefly thatthis mounting includes on instrument-supporting assembly 25 having aadjustable pad 25 providing a seat on which the instrument, which may bea camera (not shown), is clamped. The pad 25 provided with the usualinstrument stud and thumb wheel assembly 28. The locking collar assembly24 includes an upper offset apertured lug 32 on which the assembly 25 isadjustably mounted and to which it is adapted to be adjustably clampedby means of a clamping knob 34.

Referring now to Figs. 2, 3 and 9, the split elbow I0 comprises twoseparable, similar and complementary L-shaped sections 36 and 38. Thetwo sections 36 and 38 are initially formed in one piece as a unit, asfor example, by a die casting operation and finished to form an elbowfitting in which the two sections are maintained spaced from each otherby means of a relatively thin, elongated, frangible connecting web 40(Figs. 3 and 9) which extends vertically along two opposed edges of theleg portion I2 and transversely across the horizontal arm I4 and acrossthe elbow portion IB. The vertical leg portion I2 is, for convenienceand lightness, relieved as at 42 to provide an internal vertical boreand the arm I4 is similarly relieved as at 44 with the twlo relievedportions being separated by a channel 46 in the metal across which thefrangible web 40 extends. The initially formed or cast elbow is splitlongitudinally along the major outside surface thereof to provide a pairof opposed surfaces 48 and 50 which extend from the lower end of the legI2 around the elbow portion I6 to the end of the arm I4. The split inthe outer side of the initially formed or cast elbow is interrupted onlyby the vertically extending web 40 (see Figs. 5 and 6). The lower wallof the arm I4 is split as at 52 along a minor region diametricallyopposed to the major split portion of the elbow and thus, in theinitially formed or cast article, the two sections 35 and 38 thereof aremaintained slightly spaced from each other with the frangible web 40constituting the sole inter-connecting means between these two initiallyintegral parts.

The frangible web is broken along its length and this is readilyaccomplished by the simple procedure of misaligning the two sections 36and acre-voc '35 lay-.applying spreading pressure thereto sun-icient'`to fracture the webalong an 'irregular line as clearly .shown by thestippling of Fig. 3 and.E which fracture also appears iniFigs. 9, lo, iland' 12 `where the two parts 36 and 38 are sepa- .rated from eachother.A. portionfoi thei fractured web it also appears in Fig. l.

The web It, when fractured in the manner setfcrth above, constitutes anVelongated fulcrum 'by means of which the two parts when assembled uponeach. other in the instrument mountin'gr may be rocked to a slightdegreev relative to each other. In the assembled structure` a resilientgasket'li may be inserted 1between the two parts 36 .and 38 at the baseof' the'arm it (Figs. .3ifa'nd e) and a second .resilient gasket 5c may:extend between the opposedV faces i8 and til of the sections along theopposedfaces of theelbow portion It to limit or restrain the rockingmovement between the two sections.

From the above description, it lwill be seen thatwhen the composite armifi is compressed `s'oafs to roel: the sections 3h and 38 about thefulcrum axis of the `web 4G and bring the outer ends of the arms towardeach other as shown Vin Figs. 5, 7, l1 and 12, there will .bea wideningof the distance between the-opposed surfaces lli! and 5l! `of the`composite leg l2, thus in effect, increasing the diameter of thecomposite leg l2 by a spreading action so that the outside surfacesofthe twov parts 35 and Se will bear against the inner surface `of thebase socket i3 and bind vthe leg: t2 in the socket ifsto preventrotational movement of the elbow structure i@ as a whole about avertical axis. Upon release of compressional force on the composite armill, the resilient gasket 54 in a measure serves as a cushion bufferbetween the two sections 3S and 3S of the arm so as to hold them inproper position to facilitate turning movement oi the elbow about thevertical axis of the leg i2.

Inasmuch as the two sections 3e and til of the split elbow in theregions of the leg E2.' are closely encased `within the verticallyextending cylindrical confines of the base socket, there is littleopportunity for the opposed contiguous fracture areas of the web 4c tobecome separated to adegree sufficient to permit longitudinal shiftingmovement of one section relative to the other.

The opposed fractured areas are precisely, and

even the microscopically small ridges of the one extend into the valleysof the other and vice versa and the only relative movement between thesetwo opposed surfaces is, an extremely limited rockingY movement.

By the same token, the so-called spreading orA contracting movements ofthe sections of the composite split leg i2 is the result. of suchtilting or rocking movement between the se"- tions on the fulcrurn axisof the web wherein the surfaces 138 and 5@ recede from or approach eachother respectively. The spreading and contractingl movements ofthesections of the split arm i4, however, is of a diierent nature. In thisinstance, since the-axis of the fractured web 4l! is perpendicular tothe axis of the cornposite split arm ifi, rocking of the two sections 35and 38 will effect equal recession and approach of the surfaces i3 and5@ and of the opposed surfaces along the split portion E2.

Referring now to Figs. l and 4, the locking collar 24 includes. a bodyportion 6D provided with a transverse opening 62 therein through whichthe composite split arm icl of the elbowv it extends and onwhieh arm thelockingV collar vis Vi5 supported for angular tilting movement about ahorizontal axis. The body I6 includes a yield'- able friction band @flwhich issplit medially and circumferentially therearound as at 65 (Fig.2) and which encompass the arm ill and is movable into and out ofclamping engagement with the latter. The straps or sections of the splitband S45' are resilient and are normally sprung outwardly so as torelieve their gripping action Vonthe split arm i i and they are capableof being forced into gripping engagement with the arm in the manner of abrake band by means of a pair of attachment lugs t@ which areoperatively connected through a train of mechanism about to be describedto acompression spring 68 associated with an operating handle or pistolgrip assembly le.

The pistol grip assembly lil includes a barrel portion l2, the forwardend of which projects through a sleeve or thrust bushing lli yieldinglyand frictionally held in an offset apertured lug 'iii provided on thebody portion of the locking assembly 2e. The barrel 'i2 projects intothe casing 'il of the pistol grip assembly and is provided with aclearance slot 'i8 through which there extends the upper end of atrigger member 33 which. is pivcted as at di. to the casing 11 and whichdepends from the latter. The casing 'il is provided with a triggerhandle Bil in which the trigger Trl is guided. The sleeve lll and barreli2 are secured together against relative turnmcvf-rnent by means of apair of screws 85 which p through the sleeve and into the wall of theel. The body portion 'il including the handle together with the barreli2 are capable ci lateral swinging movement about the axis of the barrelto accommodate the natural position ci the wrist and hand duringoperation of the instrument mounting.

The pressure spring te is disposed within the barrel 12' adjacent itsrear end and pressure eX- erted by 'the spring is adapted to be appliedto the clamping bands t!! of the locking collar 2d through the medium ofa sectional thrust rod including a rear rotatable section 38 and a frontnon-rotatable section 53, both sections being disposed within the barrel'i2 in end-to-end relationship. The non-rotatable section gli isprovided with an ear which projects upwardly through a slot provided inthe barrel 'i2 in the upper regions thereof and which slot is of fairlylarge circumferential extent, in order to give a wide angle ci swingingmovement to the pistol grip handle Ei. The rear rotatable rod section5.23 is provided with a slot 96 in register with the slotl and throughwhich the trigger member 8! extends. The rear end of the rotatable rodsection it slotted as at and a guide pin lli!) carried by the barrel 'l2projects through the slot QS so as to connect the barrel and rod sectionfor turning movement in unison while still permitting relative slidingmovement of the rodsection within the barrel. The trigger member 331sadapted to bear at mi against one end of the slot in the rod section @iland the forward movement of the trigger member 85 and consequently oftherod section 8S, is limitedk by a stop surface iii@ provided on the body'El'.

effective length of the non-rotatable rod section @El is capable ofbeing varied by means of a pin ich which extends through a bore ittpro'- vided in the rod section E@ and which has its rear end projectingbeyo, *l the end of the rod section si! and bearing ag inst the end' ofthe rods'ec'- tion 33. V'lhe forward end of thev pin` Illia'r i'sthreadably received in the forward end of the rod section 90 and anadjusting knob I I6 secured to the extreme forward end of the pin |66 isprovided so that the pin may be shifted in one direc- -tion or the otherthrough the section 36 to increase or decrease its effective length andthus determine the throw of the friction bands 64. The trigger member 83is normally held against the rear end of the slot 33 by means of aspring pressed plunger |I2 disposed within a bore provided in therotatable rod section 88, The rear end of the barrel I2 threadablyreceives an adjusting plug |54 by means of which the compression oi thespring 68 may be varied to in turn vary the pressure applied to thefriction bands -Y From the above description it will be seen that whenno pressure is applied to the trigger member 86 the spring 68, actingthrough the two rod sections 38 and 96, will apply full pressure to thefriction bands 64 tending to contract the same on the horizontal arm I4of the split elbow IB, thereby not only holding the locking collar orbrake 24 against turning movement about the horizontal axis of the arm,but also compressing the split end of the arm i4 and spreading the splitleg I2 thereof in the manner previously described to lock the splitelbow against turning movement about a vertical axis. The instrumentsupport or pad 26 is thus locked against swinging movement about eithera vertical or horizontal axis. Upon depression of the trigger member 33the rotatable rod section 83 will be moved to the left as viewed in Fig.4, thereby compressing the spring 68 and allowing the rod section 96 tofollow the movement of the rod section 33 to release the pressure on thefriction bands 6d and permit the split sections 36 and 38 of thecomposite arm I4 to move away from each other. Pressure of the splitsections of the leg I2 against the inner wall surface of the base socketI8 is thus relieved so that the split elbow IE) is capable of turningmovement within the base socket. At the same time the relieving ofpressure by the friction bands 64 on the arm I4 permits the lockingcollar 24 to be swung about the horizontal axis of the arm to tilt theinstrument support or pad 26 in a fore and aft direction.

The instrument mounting of the present invention is capable of two maintypes of control.

The instrument support or pad 26 may be locked in a xed position againstswinging movement in elevation about the horizontal axis of the arm I4in a fore and aft direction, or it may be locked against panoramicswinging movement about the vertical axis of the leg |2 and theinstrument Support may be released for both types of movementsimultaneously upon depression of the trigger member 8D. Alternatively,the control means may be so conditioned that release of the triggermember 36 is incapable of locking the instrument support 26 againstpanoramic swinging movement and is capable only of locking the support26 against fore and aft swinging movement.

The control means for effecting these two types of locking action isbest illustrated in Figs. 1 and 5 to 8 inclusive. As shown in theseviews, a cap member |22 is telescopically received over the end of thesplit arm I4 and is provided with a centrally disposed wedge cam member|24 having a cylindrical surface |26 somewhat greater than ahalf-cylinder and having a flat surface |28 extending across the opposedends of the cylindrical surface |26. The ends of the cylindrical surface|26 are relieved as at |30 to 8 provide surfaces which are lesseccentric with respect to the axis of the cam I 24 than is theeccentricity of the cylindrical surface |26. When the cap member |22 isin position on the end of the arm I4, the cam member |24 is adapted toproject into the end of the bore 44 and, with the cam assuming theposition shown in Fig. '7, the cam is nested within the concave innersurface of the bore 44 so that sufficient clearance is provided wherebythe two sections 36 and 38 of the arm I4 may be rocked about the axis ofthe fulcrum 40 and thus contracted or expanded at will.

When the cam |24 assumes the position shown in Fig. 8, wherein it is atright angles to the position formerly described in connection with Fig.7, it is nested within both concavities of the two sections 36 and 38and therefore it serves to maintain these sections separated in theirexpanded positions. With the cam |24 in this latter position, thefriction bands 64 are incapable of compressing the split arm I4 andtherefore the two sections 36 and 38 are maintained in such a positionthat the leg I2 of the elbow I0 is contracted, thus allowing panoramicswinging movement of the instrument support.

An adjusting screw I3I extends through the wall of the section 36, isthreaded therein, and has a rounded end |33 capable of projecting intothe bore 44 and into the path of movement of the surface of the cam |24.The position of the screw I3| may be adjusted to vary the spread of thesections 36 and 38 of the split arm I4 when the cam |24 assumes theposition shown in Fig. 8. Stated in other words, the adjusting screw IBIserves to vary the effective diameter of the bore 44.

The cam |24 is centrally secured to the inside of the cap member |22 bymeans of a screw |32 which extends through the cap centrally thereof andis threadedly received in the cam |24. The screw |32 has secured theretoan operating lever |34 which is provided with a spring-pressed detent|36 designed for cooperation with a pair of depressions |31 provided onthe outer surface of the cap and by means of which the lever |34, andconsequently of the cam |24, may be locked in either of two selectedpositions. Suitable labeling or designations of the position of thelever |34 may be inscribed on the outer surface of the cap |22 and, asshown in Fig. 7, when the lever |34 is in the vertical position labelledLock, the cam |24 assumes the position shown wherein freedom of rockingmovement between the two sections 36 and 38 is made possible, so thatwhen pressure is applied by the friction bands 64 from the coil spring68 tending to contract the sections of the split arm I4, the sections ofthe split leg I2 are spread apart thus applying pressure to the innerwall of the base socket |8 and preventing panoramic swinging movement ofthe instrument support 26. When the lever |34 assumes the horizontalposition shown in Fig. 8 labelled Pan, the cam |24 assumes the positionshown wherein the two sections 36 and 38 are spread apart and areincapable of being moved toward each other. In this position of the cam,the two sections of the leg I2 are positively contracted and no pressureis brought to bear on the inner surface of the base socket I8 so thatpanoramic swinging movement of the instrument support 26 is at all timesavailable.

The cap I 22 is adapted to be securely held in its position over the endof the arm I4 by means of a locking pin l-38 having a knurled head M0Yand which extends through an opening |42 in the cap |22 and isthreadedly received in the composite arm I4.

I claim:

1. In an instrument mounting, a split elbow structure having a verticalleg adapted to be telescopically received within a vertically extendingbore of a base socket, a horizontal arm adapted to receive thereover andsupport thereon a locking sleeve of an instrument support, and aconnecting curved elbow section, said elbow structure being splitlengthwise and substantially centrally thereof (see Figs. l, 5, '7, lo,l1 and l2) and providing two spaced apart complementary half-sections,and means interposed between said sections at spaced points on astraight line extending lengthwise of the vertical leg of said elbowstructure and providing a fulcrum axis whereby said sections may berocked relative to each other about said fulcrum axis whereby movementof the complementary sections of the armtcward each other will causemovement of portions of the complementary sections of the leg away fromeach other and thereby adapted to force the latter sections intofrictional contact `with the inner wall of said vertically eX- tendingbore of the base socket.

2..In an instrument mounting, a split elbow structure having a verticalleg adapted to be telescopically received within a vertically extendingborc of a base socket, a horizontal arm adapted toreceive thereover andsupport thereon a locking sleeve of an instrument support, and `aconnecting curved elbow section, said elbow structure being splitlengthwise and substantially centrally `thereof and providing two spacedapart complementary half-sections, and a relativelyf thin web having atleast a portion thereof formed on one of said sections and bearingagainst the other section and extending along a straight line adjacentand parallel to the inner edges of the leg portions of said elbowstructure and providing a fulcrum axis about which said sections may berocked throughout a limited extent relative to each other.

3. A split elbow structure ior instrument mountings of the characterdescribed having an outwardly extending leg at one end thereof, anoutwardly extending arm at the other end thereof, and an interconnectingcurved elbow portion medially thereof, said elbow structure being splitlengthwise and substantially centrally thereoic to provide two spacedapart complementary half-sections, and a relatively thin web of straightline configuration extending along the region or the inner edges of thecomposite leg sections between said sections and providing a fulcrumaxis about which the sections may be tilted relative to each other. f

Il. A split elbow struct-ure for instrument mountings ci the characterdescribed having a leg and an arm extending at angles to each other, andan interconnecting curved elboiv section, said elbow structure beingsplit lengthwise and substantially centrally thereof to provide spacedapart complementary half-sections, and a relatively thin web of straightline conguration extending along the region of the inner edges of thecomposite leg sections and transversely across the elbow section andproviding a fulcrum axis about which said sections may be rockedrelative to each other.

5. A split elbow structure for instrument mountings of the characterdescribed having a I0 leg and an arm extending VatY angles to Ieachother, and an interconnecting curved elbow section, Vsaid elbowstructure being split lengthwise and substantially `centrally thereof to`provide complementary half-sections, and a relatively thin linearyfiange of straight line coniiguration formed on each of' said sectionsand extending along the respective inner edge of the leg portion thereofand transversely across the elbow section thereof to hold saidcomplementary sections in spaced relation to each other, said flangesbeingin direct opposition and edge-toedge contact -with each other andproviding a fulcrurn` axis labout which the sections may betiltedrelativeto each other.

6. A split elbow structure for instrument mou-ntings ofV the ycharacterdescribed having a leg `and an arm extendingat right angles to eachother, and an interconnecting curved elbow section, said elbow structurebeing split longitudinally and substantially centrally'to providecomplementary half-sections, and a relatively thin `web of straight-lineconfiguration extending across the region ofth'e inner edges of thecomposite leg sections and transversely across the elbow section andaxis of the arm section, said web having a portion 'thereof formed onone of said `secti'onsand another portion thereof formed on theother-section with tl'ie'medial regions of the web being fractured alongits lentire length to provide irregular mating surfaces which constitutean iniinite series of available fulcrum points arranged generallyinalignment for rockingV movement of the two 'sections' relative to eachother.

'i'. An instrument mountingcomprising a base socket member having avertical cylindrical wall, a split elbow structure having 'a verticalleg adapted to be telescopically 'received within said socket and ahorizontal Varm adaptedto receive thereover and'supportithereon alocking sleeve of an instrrmentV support, said elbow Vstructure beingsplit lengthwisearrd substantially v'centrally thereof and providing twocomplementary halfsections, said sections being provided on their innerfaces with a iulcrum bearing whereby rocking movement of the sections oneach other to move the complementary sections of the horizontal armtoward each other and force the complementary sections of the verticalleg into frictional holding engagement with the cylindrical wall of saidsocket, the complementary sec-tions or said horizontal arm beingrecessed internally to provide a substantially cylindrical bore withinthe composite arm, a cam telescopically received in said bore and havinga generally semi-cylindrical outer surface designed for wedgingengagement with the opposed walls of said bore, said cam when in oneposition of adjustment having its semi-cylindrical surface in spreadingengagement with the opposed walls of said complementary sections of thehorizontal arm, and when in another position of adjustment having itssemi-cylindrical surface substantially wholly contained within one wallof said bore to relieve the pressure applied to said walls and permitrocking movement of the sections relative to eeach other, and manualmeans for moving said cam to either of said positions of adjustment.

8. An instrument mounting comprising a base socket member having avertical cylindrical wall, a split elbow structure having a vertical legadapted to be telescopically received within said socket and ahorizontal arm adapted to receive thereover and support thereon alocking sleeve of an instrument support, said elbow structure beingsplit lengthwise and substantially centrally thereof and providing twocomplementary halfsections, said sections being provided on their innerfaces with a fulcrum bearing whereby rockingmovement of the sections oneach other to move the complementary sections of the horizontal armtoward each other and force the complementary sections of the verticalleg into frictional holding engagement with the cylindrical wall of saidsocket, the complementary sections of said horizontal arm being recessedinternally to provide a substantially cylindrical bore within thecomposite arm, a cup-shaped cap member telescopically receivable overthe end of said arm, a cam mounted for rotation on said cap membercentrally thereof and receivable on said bore when said cap member is inposition on the arm, said cam having a generally cylindrical outersurface designed for wedging engagement with the opposed walls of saidbore, said cam when in one position of its adjustment for itssemicylindrical wall in spreading engagement with the opposed walls ofsaid complementary sections of the horizontal arm, and when in anotherposition of adjustment beingsubstantially wholly contained within onewall of said bore to relieve the pressure applied to said walls andpermit rocking movement of the sections relative to each other, anoperating finger secured to said cam and projecting through the wall ofsaid cap member and movable with the cam between two positions ofadjustment and detent means for holding said operating finger in eitherposition of adjustment.

9. An instrument mounting comprising a base socket member having avertical cylindrical wall, a split elbow structure having a vertical legadapted to be telescopically received within said socket and ahorizontal arm adapted to receive thereover and support thereon alocking sleeve of an instrument support, said elbow structure being l2split lengthwise and substantially centrally thereof and providing twocomplementary half-sections, said sections being provided on their innerfaces with a fulcrum bearing whereby rocking movement of the sections oneach other to move the complementary sections of the horizontal armtoward each other and force the complementary sections of the verticalleg into frictional holding engagement with the cylindrical wall of saidsocket, the complementary sections of said horizontal arm being recessedinternally to provide a substantially cylindrical bore within thecomposite arm, a cup-shaped cap member telescopically receivable overthe forward end of said arm and having a cylindrical flange encompassingsaid arm for limiting the spreading movements of the complementarysections thereof, a cam mounted for rotation centrally within said capmember and projecting into said bore, said cam having a generallysemi-cylindrical outer surface designed for wedging engagement with theopposed walls of said bore, said cam when in one position of adjustmenthaving its semicylindrical wall in spreading engagement with the opposedwalls of said complementary sections of the horizontal arm, and when inanother position o adjustment having its semicylindrical surfacesubstantially wholly contained within one wall of said bore to relievethe pressure applied to said walls and permit rocking movement of thesections relative to each other, means extending through said cap memberfor moving said cam to either of its two positions of adjustment, andmeans for securing said cap member to one of the complementary sectionsof said arms.

HARRY S. PASTURCZAK.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,424,499 Pasturczak July 22, 1947 2,524,473 Pasturczak Oct.3, 1950

